Their business model relies on license sales. The 2-free allowance is a loss leader to get you into the ecosystem.
: Most standard IP cameras use 1 license, but complex devices like multi-lens cameras or video servers may require multiple licenses per physical unit. to pool your existing NAS licenses? Surveillance Device License Pack | Synology Inc. synology surveillance station license free
Instead of hunting for a "license free crack," install or Frigate (via Docker) on your Synology, or install Blue Iris on an old Windows PC. Their business model relies on license sales